Improvement of lipase production at different stirring speeds and oxygen levels

Lipase production by a Brazilian wild strain of Yarrowia lipolytica at different stirring speeds and air flow rates was studied. The relationship among lipid consumption, cell growth and lipase production by this microorganism is presented. The most pronounced effect of oxygen on lipase production was determined by stirring speed. Maximum lipase activity was detected in the late stationary phase at 200 rpm and an air flow rate of 1-2 dm³/min (0.8-1.7 vvm) when the lipid source had been fully consumed. Higher stirring speeds resulted in mechanical and/or oxidative stress, while lower stirring speeds seemed to limit oxygen levels. An increase in the availability of oxygen at higher air flow rates led to faster lipid uptake and anticipation of enzyme release into the culture medium. The highest lipase production was obtained at 200 rpm and 1 dm³/min (0.8 vvm)

Analysis Of Street Ecstasy Tablets By Thin Layer Chromatography Coupled To Easy Ambient Sonic-spray Ionization Mass Spectrometry

Ecstasy is a famous illicit drug with varying drug composition, but it usually contains 3, 4-meth-ylenedioxymethamphetamine (MDMA) as the main active ingredient. The common proce-dure to identify ecstasy tablets uses testing kits, but its low specificity may lead to false posi-tives. Thin layer chromatography (TLC) is used worldwide in forensic investigations due to its simplicity, low-cost and versatility but may also lead to false positives. In this study, TLC sepa-ration of seven common ecstasy drugs: MDMA, metamphetamine, 3, 4-methylenedioxyeth-ylamphetamine (MDEA), 3, 4-methylenedioxyamphetamine (MDA), amphetamine, caffeine and lidocaine was attained, and twenty five apprehended street ecstasy tablets analyzed by TLC. Easy ambient sonic-spray ionization mass spectrometry (EASI-MS) was then performed directly on the surface of each TLC spot for MS characterization. The combination of TLC with EASI-MS is shown to provide a relatively simple and powerful screening tool for forensic analy-sis of street drugs with fast and indisputable results.15222227Renfroe, C.L., (1986) J. Psychoactive Drugs, 18, p. 363Jeffrey, W., (2004) Clarke's Analysis of Drugs and Poisons In Pharmaceuti-cals, Body Fluids and Postmortem Material, , Moffat, A.Osselton, M.Widdop, B.Galichet, L., eds.London, UK: Pharmaceutical PressSherlock, K., Wolff, K., Hay, A.W., Conner, M.J., (1999) Accid. Emerg. Med, 16, p. 194Sadeghipour, F., Veuthey, J.L.J., (1997) Chromatogr. A, 787, p. 137Bogusz, M.J.J., Chromatogr, B., (2000) Biomed. Sci. Appl, 748, p. 3Kato, N., Pharm, B., Fujita, S., Pharm, B., Ohta, H., Fukuba, M., Pharm, M., Hayakawa, K., (2008) J. Forensic Sci, 53, p. 1367Zakrzewska, A., Parczewski, A., Kazmierczak, D., Ciesielski, W., Kochanaa, J., (2007) Acta Chim. Slov, 54, p. 106Ifa, D.R., Wu, C., Ouyang, Z., Cooks, R., (2010) G. Analyst, 135, p. 669Alberici, R.M., Simas, R.C., Sanvido, G.B., Romão, W., Lalli, P.M., Benassi, M., Cunha, I.B.S., Eberlin, M.N., (2010) Anal Bioanal. Chem, , in pressHarris, G.A., Nyadong, L., Fernandez, F.M., (2008) Analyst, 133, p. 1297Chen, H., Gamez, G., Zenobi, R.J., (2009) Am. Soc. Mass Spectrom, 20, p. 1947Ifa, D.R., Gumaelius, L.M., Eberlin, L.S., Manicke, N.E., Cooks, R., (2007) G. Analyst, 132, p. 461Haddad, R., Sparrapan, R., Kotiaho, T., Eberlin, M.N., (2008) Anal Chem, 80, p. 898Santos, V.G., Regiani, T., Dias, F.F.G., Romão, W., Klitzke, C.F., Coelho, F., Eberlin, M.N., (2010) Angew. Chem. Int. Ed, , submitHaddad, R., Sparrapan, R., Eberlin, M.N., (2901) Rapid Commun. Mass Spectrom, 2006, p. 20Lalli, P.M., Sanvido, G.B., Garcia, J.S., Haddad, R., Cosso, R.G., Maia, D.R.J., Zacca, J.J., Eberlin, M., (2010) N. Analyst, 135, p. 745Haddad, R., Catharino, R.R., Marques, L.A., Eberlin, M.N., (2008) Rapid Commun. Mass Spectrom, 22, p. 3662Saraiva, S.S., Abdelnur, P.V., Catharino, R.R., Nunes, G., Eberlin, M.N., (2009) Rapid Commun. Mass Spectrom, 23, p. 357Abdelnur, P.V., Eberlin, L.S., Sá, G.F., Souza, S.V., Eberlin, M.N., (2008) Anal. Chem, 80, p. 7882Sawaya, A.C.H.F., Abdelnur, P.V., Eberlin, M.N., Kumazawa, S., Ahn, M.-R., Bang, K.-S., Nagaraja, N., Afrouzan, H., (2010) Talanta, 81, p. 100Saraiva, S.A., Abdelnur, P.V., Catharino, R.R., Nunes, G., Eberlin, M.N., (2009) Rapid Commun. Mass Spectrom, 23, p. 357Haddad, R., Sparrapan, R., Kotiaho, T., Eberlin, M.N., (2008) Anal. Chem, 80, p. 898Haddad, R., Milagre, H.M.S., Catharino, R.R., Eberlin, M.N., (2008) Anal. Chem, 80, pp. 2744-2750Eberlin, L.S., Abdelnur, P.V., Passero, A., de Sa, G.F., Daroda, R.J., de Souza, V., Eberlin, M.N., (2009) Analyst, 134, p. 1652Figueiredo, E.C., Sanvido, G.B., Arruda, M.A.Z., Eberlin, M.N., (2010) Analyst, 135, p. 726Gao, L., Cooks, R.G., Ouyang, Z., (2008) Anal. Chem, 80, p. 4026Syms, R., (2009) Anal. Bioanal. Chem, 393, pp. 427-42